This application generally relates to an acoustic liner for a duct. More particularly, this application relates to a splice for covering seams in the acoustic liner.
Conventional turbine and turbofan engines for aircraft include a plurality of fan blades that rotate within a duct commonly known as a fan case. The fan case serves as a protective covering to protect the fan blades and the aircraft. Further the fan case channels airflow into the turbine engine. The inner surface of the fan case is constructed to withstand impacts from objects that may come into contact with the fan case and includes acoustical features to reduce the noise emitted from the engine.
It is known to provide a fan case liner with a layer of noise attenuation structures and a face layer including a plurality of openings. The face layer is typically a thin sheet of metal or composite material mounted over the noise attenuation structure. Noise causing pressure disturbances emanate through openings within the face layer into the noise attenuation structure where the pressure disturbances dissipate to reduce the total amount of noise.
The face layer forms the inner surface and typically includes at least one seam to accommodate assembly tolerances as well as accommodating loads generated by thermal expansion. A splice is bonded over the seam to protect the edges of the face sheet and the underlying noise attenuation structure. The splice is typically a solid strip of material that overlaps each side of the face layer. The splice is bonded with an adhesive to the face layer on either side of the seam. The adhesive and splice combine to block openings through the face layer to the noise attenuation structure. Disadvantageously, this results in an acoustically dead area within the liner assembly that does not absorb noise. The acoustically dead area reduces the effectiveness of the noise attenuation structures of the acoustic liner.
Accordingly, it is desirable to develop a splice for an acoustic liner that is acoustically active to improve noise attenuation properties of a liner assembly.